Embodiments of the disclosed technology relate to a three dimensional (3D) display panel and a method of manufacturing a phase difference plate.
Stereoscopic display has become a trend of the display field. And, the hypostasis of the stereoscopic display is to produce a stereoscopic effect by utilizing a parallax, i.e., a left-eye picture is seen by the left eye of a person, and a right-eye picture is seen by his right eye. The left-eye and right-eye pictures are a pair of stereoscopic images having the parallax.
One mode to achieve the stereoscopic display is of a serial type, i.e., at a first time, a left-eye picture is displayed on a display and the displayed picture is only seen by the left eye of a viewer at this time; and at a second time, a right-eye picture is displayed on the display and the displayed picture is only seen by the right eye of the viewer. The pictures will be retained on retinas of human eyes for a period of time, so as to give the person a feeling that the left-eye and right-eye pictures are simultaneously seen by the left and right eyes. Thus, a stereoscopic sensation is produced.
Another mode to achieve the stereoscopic display is of a parallel type, i.e., at the same time, content for a left-eye picture is displayed by a part of pixels on a display, and content for a right-eye picture is displayed by a part of pixels. The displayed right-eye picture only can be seen by the right eye and the displayed left-eye picture only can be seen by the left eye through devices such as gratings, polarized glasses, so as to produce the stereoscopic sensation.
Polarized glasses type stereoscopic display is a currently mainstream technology in the field of stereoscopic display, and the basic structure of this technology is to install a device for adjusting a polarization direction of light being emitted in front of a display panel. The device may be a phase difference plate, a liquid crystal cell, or other device capable of adjusting the polarization direction of the light emitted from different pixels. The principle of stereoscopic display of the phase difference plate is as shown in FIG. 1, and from top to bottom, there are: a picture displayed by the display panel, a phase difference plate, a picture formed by the light passing through the phase difference plate, and polarized glasses for viewing. On the display panel, a right-eye picture is shown in a row, and a left-eye picture is shown in a row. A phase difference plate is disposed in front of the display panel, one row has a λ/2 retardation (λ is the wavelength of light), and one row has a zero retardation. The light emitted from pixels for the portion having the λ/2 retardation rotates, after passing through the phase difference plate, 90° in its polarization direction. Thus, only a light emitted by right-eye pixels can be seen by the right eye and only a light emitted by left-eye pixels can be seen by the left eye when polarized glasses, polarization directions of which for the left and right eyes are perpendicular to each other, are put on, so as to produce the stereoscopic effect. Alternatively, one row has a λ/4 retardation and one row has a 3λ/4 retardation in a scheme.
In various polarized glasses stereoscopic displays, a technology in which a phase difference plate is employed is the most favorite. Its basic structure is that, the phase difference plate is attached to the display panel after being precisely aligned thereto. Different phase retardations can be produced in different regions on the phase difference plate, so that light from different pixels is emitted in different polarization directions and a viewer can see a 3D effect when wearing polarized glasses.
Currently, a method of manufacturing a 3D display panel based on a phase difference plate is: firstly, the phase difference plate is produced on a substrate (e.g., a glass or a thin film substance) for the phase difference plate, and then the phase difference plate is attached to the display panel with a double-side tape or other adhesives. Its base structure is as shown in FIG. 2. A phase difference plate 2, which is produced on a substrate 211 for the phase difference plate, is adhered to an upper polarizer 112 of a display panel 1 with an adhesive 212.
Problems present in the above manufacture process of the phase difference plate lie in that, when the phase difference plate is aligned and attached to the display panel, it is always difficult to align precisely and the accuracy is very low, leading to a very low yield and severe crosstalk for a 3D product which is manufactured in this manner; moreover, as a layer of the adhesive 212 and the substrate 211 for the phase difference plate are added, loss of light will occur; and a distance from a light emitting point (red, green and blue light emitting points on a display substrate) to the phase difference plate is increased, thereby reducing the viewing angle. These problems have severely hindered the development of the phase difference plate type 3D display.